A wood grain pattern is created by cells that make up a piece of natural wood. As the piece of wood is processed, the cells are split open exposing pores in the wood. The pores create a pattern of valleys and rifts that result in the wood grain pattern. Valleys are large pores that are long and narrow and have a texture and depth such that they are easily discernable within a grain pattern. Rifts are smaller pores that are less distinct. The rifts can have various sizes and be randomly spaced at variable concentrations throughout the grain pattern based on the cell formation of the wood. Because rifts create less contrast, the rifts contribute to a subtle tonal background pattern within the wood grain pattern.
Recreating a natural wood grain pattern in a molded article such as a door skin is difficult. Traditionally, an image of a natural wood grain pattern has been used to recreate the wood grain pattern in the molded article. For example, a line pattern image based on the image of the natural wood grain can be printed onto an exterior surface of the door skin. However, the printed pattern created on the door skin is two dimensional and lacks the depth or texture found in the natural wood grain pattern. Moreover, depositing print ink directly onto the door skin creates a wood grain pattern that may lack crisp definition of wood grain lines and adequate contrast of varying tones found in the background of the natural wood grain pattern.
In an attempt to add depth and texture to create a more realistic wood grain pattern, a door skin can be pressed with an embossing plate etched with a wood grain pattern. The wood grain pattern of the embossing plate can be created from an image of the natural wood grain pattern where the image includes ticks that correspond to the valleys within the image of the wood grain pattern and background tonal portions that correspond with the rifts. The embossing plates can be etched by patterning a resist on the metal and subjecting the surface to acid to remove portions of the metal plate creating a textured surface including the tick and tonal patterns. The etched plate is thus a negative of the pattern to be formed in the door skin.
Due to limitations arising during the process of etching the embossing plate, the size, shape, and configuration of the wood grain pattern associated with the tick and tonal portions can create inaccurate formations. For instance, when walls of the plate between adjacent ticks and/or tonal portions are too narrow, the acid used to etch the embossing plate can eat into the sides of the tick and/or tonal portions, destroying delineation between adjacent ticks and/or tonal portions. In order to prevent the acid from etching between adjacent ticks and/or tonal portions, the image of the natural wood grain pattern can be modified such that the ticks and/or tonal portions are spaced apart a predetermined distance. For example, tonal portions can be arranged in a geometric pattern where all projections within a tonal portion are uniformly spaced from one another. However, the resulting wood grain pattern embossed into the door skin may not accurately resemble a natural wood pattern and can create a configuration and/or appearance that upon close appearance may not appear realistic.
Therefore, there is a need for an embossing plate for molding a door skin or other molded article with a wood grain pattern that more accurately captures the subtle contrasts necessary to create realistically appearing wood ticks and background tonal portions as found in a natural wood grain pattern. Yet a further need in the art is to form an embossing plate useful to create a door skin having wood grain pattern with features and surface characteristics acceptable to consumers both aesthetically and from a price point. Additionally, there is a need for a door skin and a door formed from two door skins that have naturally appearing wood grain images.